I know that with the passing of Mr. Riley that Bachmann pretty much as abandoned 1:20.3 market.
What I also note is the other big 1:20.3 was Accucraft/AMS. I have not seen much from them either lately. I presume the AMS line pretty much has covered most rolling stock though it seems again some items are getting thin in stock. However, new locomotives seem to have vanished.
A year or more back it seems that Accucraft made some long range plans for a C-18, SP #18 and I believe WSL #15 in live steam.
I am guessing that the market is pretty much dead or minimal at this point.